Monday, April 6, 2009
TangBand Reverse Tapped Pipe
Or more commonly known as a reverse tapped horn, though that is really an oxymoron. In any case, I built a prototype of this on a lark using a single Tang Band W69-1042J 6"x9" Subwoofer using 1/" MDF (yuck !!). I played around with stuffing and finally left it unstuffed. Despite being unstuffed, the bass is non-resonant ie. non boomy. Note that I did take the time to add side - to side braces (not shown in picture). Well, it isn't going to displace the big horn sub, as I can find the limits of its excursion IF I want to (somewhat above normal listening levels though) but it was a good cheap experiment. Excursion is lower than expected, for the amount of sound it produces, but as I said, I can find it's limits Iif I want. Probably solid to 30 - 35 Hz with output below that. Remember, this is a 6 x 9 87db.w/m 8 ohm driver keeping up with a pair of 95 - 97+ db/w/m speakers (depending on what is currently hooked up) driven by a cheapo 100 W plate amp.
I wonder what would happen if I took off driver access plate and allowed the driver to breathe through more than the small terminus that it's now exposed to . Food for thought ....
Here are the input parameters and theoretical impedance curves.
Lastly, here are the observed impedance curves. Close but the 2nd impedance peak is off, probably due to differences caused buy the (inevitable) folding.